HIV transmission networks mapped to reduce infection rate

Researchers at the University of California, San Diego School of Medicine have mapped the transmission network of human immunodeficiency virus (HIV) in San Diego. The mapping of HIV infections, which used genetic sequencing, allowed researchers to predictively model the likelihood of new HIV transmissions and identify persons at greatest risk for transmitting the virus.

The findings are published online in the June 5 issue of the journal PLOS ONE.

"The more we understand the structure and dynamics of an HIV , the better we can identify 'hot spots' of transmission," said Susan Little, MD, professor of medicine at the UC San Diego AntiViral Research Center and lead author of the study.

"Not everyone who is HIV-infected is equally likely to transmit the infection to others. There are clusters of more active disease transmission. We can use this information to target treatment interventions to those most likely to transmit the virus to others and markedly reduce the number of new infections."

The researchers analyzed the HIV-1 sequence data from recently HIV-1 infected persons and their sexual and social contacts in San Diego, between 1996 and 2011. Sequence data were collected as part of routine HIV genetic testing used to determine if a virus is resistant to certain classes of HIV medications. Genetic similarities between viral sequences infecting different people were compared. Viruses from two people with a high degree of genetic similarity were suggestive of a transmission link. The scientists noted that viral similarity does not independently prove that a transmission occurred, only that the individuals are part of a closely connected transmission network.

Within the observed HIV transmission network, researchers calculated a transmission network score (TNS) to estimate the risk of HIV transmission from a newly diagnosed individual to a new partner. Participants with a high TNS were significantly more likely than those with low TNS to develop a close linkage to another person within their first year of HIV infection, suggestive of onward transmission.

Through network modeling, investigators showed that using this information to deploy antiretroviral therapy (ART) to individuals with the highest TNS resulted in a significantly greater likelihood of reduced new HIV-1 transmissions than providing ART to the same number of randomly selected individuals.

"Focusing our prevention and treatment resources to the populations at greatest risk of transmission could dramatically reduce the number of new infections associated with these populations," said Little. "Used in conjunction with traditional partner services, TNS-guided treatment and prevention interventions could markedly lower rates of new HIV infection in our community."

Related Stories

In Africa, STI testing could boost HIV prevention

date May 28, 2014

To maximize HIV prevention efforts in South Africa and perhaps the broader region, public health officials should consider testing for other sexually transmitted infections when they test for HIV, according to a new paper ...

Good news for HIV treatment as prevention

date Mar 07, 2014

The Kirby Institute at UNSW Australia welcomes early results from the PARTNER study, which has found that HIV positive gay men who are on treatment and have undetectable viral load are not transmitting HIV ...

Recommended for you

HIV reservoirs remain obstacles to cure

date May 19, 2015

Antiretroviral therapy (ART) has proven lifesaving for people infected with HIV; however, the medications are a lifelong necessity for most HIV-infected individuals and present practical, logistical, economic ...

Microclinics help keep Kenyan HIV patients in care

date May 18, 2015

A team led by researchers from UC San Francisco, Organic Health Response, and Microclinic International is reporting results of a study that showed significant benefits of microclinics—an innovative intervention ...

'Redesigned' antibodies may control HIV

date May 18, 2015

With the help of a computer program called "Rosetta," researchers at Vanderbilt University have "redesigned" an antibody that has increased potency and can neutralize more strains of the AIDS-causing human ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.